Page:Proceedings of the Royal Society of London Vol 60.djvu/248

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Variation in Portunus depurator.
227

and so the generalised probability curve would be one of unlimited range.

R. Antero-lateral.—The mean fluctuates considerably in the different groups, but there is a slight tendency to fall. Omitting the first group as being too small, it will be seen the mean falls about one unit in the whole series.

Range of deviation = 732—831 thousandths of standard, giving 25 units of variation. We select groups 6—12 (1432 individuals) for forming a frequency curve. Here the range = 736—819 thousandths, giving 21 units.

Fig . 3.—E. Antero-lateral. 1432 Individuals (see fig 2).

Variation in Portunus depurator. 227 Centroid = 11331704. ^ = 9296165. <r = 3-048978. fi, = -1-075979. /t4 = 255-659399. ft, = 0-001441. ft2 = 2-958381. r = 134-096687. ^ /3i 2 /32 -f- 6 Skewness = ft,-~*~2 =